As is known, surface bleaching of textiles is bleaching wherein the bleaching mechanism takes place on the textile surface and, thereby, removes stains and/or soils. Typical bleaching compositions contain peroxygen bleaches capable of yielding hydrogen peroxide in aqueous solutions and bleach activators to enhance bleach performance. It has long been known that peroxygen bleaches are effective for stain and/or soil removal from textiles, but that they are also extremely temperature dependent. Such bleaches are essentially only practicable and/or effective in bleaching solutions, i.e., a bleach and water mixture, wherein the solution temperature is above about 60.degree. C. At bleach solution temperatures of about 60.degree. C., peroxygen bleaches are only partially effective and, therefore, in order to obtain a desirable level of bleaching performance extremely high levels of peroxygen bleach must be added to the system. This is economically impracticable for large-scale commercialization of modern detergent products. As the bleach solution temperature is lowered below 60.degree. C., peroxygen bleaches are rendered ineffective, regardless of the level of peroxygen bleach added to the system. The temperature dependence of peroxygen bleaches is significant because such bleaches are commonly used as a detergent adjuvant in textile wash processes that utilize an automatic household washing machine at wash water temperatures below 60.degree. C. Such wash temperatures are utilized because of textile care and energy considerations. As a consequence of such a wash process, there has been much industrial research to develop substances, generally referred to as bleach activators, that render peroxygen bleaches effective at bleach solution temperatures below 60.degree. C.
Numerous substances have been disclosed in the art as effective bleach activators. For example, bleach activators having the general formula ##STR1## wherein R is an alkyl group and L is a leaving group, have been disclosed in the art. Such bleach activators have typically been incorporated into detergent products as an admixed granule, agglomerate or other type of particle. However, one problem with such bleach activators is maintaining the stability of the activator prior to use by the consumer. The bleach activator granule or agglomerate has a tendency to degrade over time which is exacerbated by exposure to environmental effects such as heat and humidity. As a consequence of this, the granule, agglomerate or other particulate form of the bleach activator must be relatively large in comparison to the other detergent ingredients in a typical granular detergent product. This, in turn, causes another problem associated with detergent product segregation in that the larger bleach activator particles tend to accumulate at or near the top of the detergent box while relatively smaller particle sized detergent ingredients accumulate at or near the bottom of the box. Additionally, particle segregation occurs during the detergent manufacturing process, leading to increased box to box variability for the detergent active ingredients. The net result of such an undesirable product segregation is decreased performance since the user scoops the product from the top to the bottom and each scoop has a disproportionate amount of bleach activator or other detergent ingredient, and similarly, the performance of product from different boxes is affected by variance in the detergent composition. Thus, it would be desirable to have a detergent composition containing a bleach activator which has improved stability prior to use, and which does not significantly segregate prior to packaging or while stored in the detergent product box. Additionally, it would be desirable to have such a detergent composition which also has acceptable physical properties, for example, acceptable flow properties for bulk handling of the composition as part of large-scale detergent manufacturing.
Yet another problem with the aforementioned bleach activators relates to the inability to advertise the sanitization effects of the above-mentioned bleach/bleach activator systems on fabrics. Currently, most government regulation agencies require that sanitization advertising claims for fabric care can only be made if a relatively high level of microbes are consistently removed from the laundered fabrics as a result of using the bleach-containing detergent product. In the past, however, the relatively large granule, agglomerate or other particle form of the bleach activator has inhibited such sanitization advertising claims in that the product segregation effects of such larger particles prevented the consistent removal of high levels of microbes from the laundered fabrics. The bleach/bleach activator delivery during the laundering process varied too widely to satisfy most governmental agency requirements for sanitization advertising claims. It would therefore be desirable to have a bleach-containing composition detergent which can be used to sanitize fabrics.
Accordingly, there remains a need in the art to have detergent composition containing a bleach activator which has improved stability prior to use. Also, there is a need in the art for a detergent composition containing a bleach activator which does not significantly segregate while stored in the detergent product box and has acceptable physical properties. Yet another need in the art remains for such a detergent composition which has a more consistent bleach/bleach activator delivery.